As I am converting C++ code, I ran into a CRrectTracker class. So I looked at Trubber band in LCL, it's basically nothing. Sorry.
Any ways, I had something in my old projects and needs to be expanded of course but is usable now I will give it away here.
Example Use:
TestBox := TGripper.Create(Self,ScrollBox1);//or any TWinControl
TestBox.BoundsRect := Rect(0,0,100,100);
TestBox.GripType := grpSphereFilled;// Or the box style.. etc
TestBox.Visible := True;
TestBox.Hint := 'This is my box';
Testbox.ShowHint := True;
I have attached the UNIT file.